Dropresize is described as 'Portable application that can automatically resize images in folders specified by the user. It resides in the system tray so it won’t interfere with your work, however it’s readily available if you want to configure it' and is an app. There are more than 25 alternatives to Dropresize for a variety of platforms, including Windows, Web-based, Mac, Linux and Android apps. The best Dropresize alternative is Image Toolbox, which is both free and Open Source. Other great apps like Dropresize are ImageMagick, Caesium Image Compressor, XnConvert and Converseen.